Cardioprotective effect of Angiotensin (1-7) on myocardial infarction: Possible role of Nitric oxide and prostaglandins.

Objective: to detect the possible cardioprotective effect of Ang-(1-7) in rat model of MI; Also, possible role of NO and PGs in this probable cardioprotective effect of Ang- (1-7) was studied. Methods: Rats were divided randomly into 6 groups (8 rats each): Group I : Control group:, Group II: rats received S.C isoprenaline at a dose of 150 mg/kg/day on two consecutive days with an interval of 24 hours between applications, Group III: rats received Ang (1-7) (576μg/kg/day) S.C for 6 days after induction of MI ,Group IV: in which rats received Ang (1-7) (576μg/kg/day)+ L-NAME in the drinking water (80 mg/l) for 6days after induction of MI ,Group V: in which rats received Ang (1-7) (576μg/kg/day) +Indomethacin 5 mg/kg/day IP for 6 days after induction of MI ,Group VI: in which rats received both Ang-(1-7)+ L- NAME and Indomethacinat dose mentioned previously. Biochemical, histopathologial , and ECG changes were studied Results: ISO –MI group exhibited a significant rise in serum cardiac enzymes and disturbed lipid profile, increased myocardial damage score and Caspase3 expression when it is compared to the normal group (p<0.001). ECG changes of rat revealed elevation ST segment, QT interval prolongation, decrease QRS duration and voltage, and accelerated heart rate. Ang-(1-7) caused significant improvement in the studied parameters ,while co-infusion of L-NAME and or indomethacin prevent this effect of Ang-(1-7) .Combined L-NAME and  indomethacin produce more deleterious effect than separate administration of them. Conclusion: Ang-(1-7) is considered one of the cardioprotective components of RAS .NO and PGs mediate the action of Ang-(1-7) and they may have an additive effect.